锁脚锚管作用机理分析

Action Mechanism Analysis of Locking Tremies

对比分析了锚杆和锁脚锚管的异同点,研究了锁脚锚管对支护结构变形和内力的影响,揭示了锁脚锚管的作用机理,提出了判断锁脚锚管是否有效和合理的标准。研究表明锁脚锚管应通过约束其沿洞轴方向的转动自由度考虑,合理的锚管长度和打入角度不仅有利于限制围岩的变形,而且有助于支护结构承载能力的发挥,一般土质隧道的锁脚锚管长度宜取2.3 m^3.0 m,打入角度宜取0°或30°。判断锁脚锚管是否合理时,可根据工程实际需要,结合承载能力发挥系数与位移限制系数确定。

The similarities and differences between locking tremies and bolts for tunnels are compared,the influences of the locking tremies to the internal force and deformation of tunnel support structures are studied,the reinforcement mechanism of the locking tremies is discussed,and the criterions for the effectiveness and rationality of the locking tremies are proposed.It is shown that the locking tremies should be considered by confining their rotational freedom degree in the direction of the tunnel axis.The rational length and angle of the locking tremies are not only advantageous to confine the deformation of surrounding rocks,but also beneficial to the effectiveness of support structures.Generally,the length and angle of the locking tremies should be （2.3） m～3.0 m and 0° or 30° respectively.Whether the locking tremies are rational or not could be decided according to the need of projects and the effective coefficient of bearing capacity or the coefficient of displacement confinement.